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ARS Home » Pacific West Area » Tucson, Arizona » SWRC » Research » Publications at this Location » Publication #165145


item McLain, Jean
item Martens, Dean

Submitted to: Biodiversity & Management of the Madrean Archipelago Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2005
Publication Date: 5/11/2005
Citation: Mclain, J.E., Martens, D.A. 2005. Climate mitigation potential of the san pedro river riparian zone. Proc. Biodiversity and Management of The Madrean Archipelago II: Connecting Mountain Islands and Desert Seas Conf., May 11-14, Tucson, AZ, pp. 491-495.

Interpretive Summary: Research into semi-arid terrestrial sinks for atmospheric C has been nonexistent due to the perceived notion that due to seasonal moisture deficits, semi-arid regions are not a source or sink for atmospheric C. Water is the most limiting resource to biological activity in semi-arid lands. The increased demands for water due to the growing human presence in the San Pedro River valley has resulted in a need for understanding the water needs of both the growing human presence and the water needs of a healthy riparian zone. The riparian area was found to have 7000 metric tons of C more compared to an equal sized area of open brushy area not within the riparian zone and may represent one of the few areas of active C sequestration studies in semi-arid areas. Water is essential for ecosystem function and loss of water from the San Pedro River will severely impact the ability to store C in the riparian area.

Technical Abstract: Carbon (C) and nitrogen (N) cycling within an open brush site, a sacaton (Sporobolus wrightii) grass and a mesquite (Prosopis velutina) grove in the riparian zone was closely linked to the yearly litter N inputs. Yearly mesquite litter fall for 2 yr was remarkably similar and averaged 4.0 g N m-2 and 65 g C m-2 soil and resulted in higher soil C content compared to other riparian vegetation. The riparian soils held 7000 metric tons more C than an adjacent nonriparian area suggesting the riparian zone processes result in a sink for atmospheric C. Water is essential for ecosystem function and loss of water from the San Pedro River will severely impact the C sink in the riparian area.